export default {
	namespaced: true,
	state: () => ({
		// 购物车的数组，用来存储购物车中每个商品的信息对象
		// 每个商品的信息对象，都包含如下 6 个属性：
		// { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
		cart: JSON.parse(uni.getStorageSync('cart') || '[]')
	}),
	mutations: {
		addToCart(state, goods) {
			//根据提交的商品的id，查询购物车中是否存在这样的商品
			//如果不存在，则findResult 为undefined；否则，为查找到的商品信息对象
			const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)

			if (!findResult) {
				//如果购物车中没有这件商品，则直接push
				state.cart.push(goods)
			} else {
				//如果购物车中有这件商品，则直接更新数量即可
				findResult.goods_count++
			}

			//通过commit 方法, 调用m_cart 命名空间下的saveToStorage 方法
			this.commit('m_cart/saveToStorage')
		},
		saveToStorage(state) {
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		updateGoods(state, goods) {
			const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)
			if (findResult) {
				if (goods.goods_state !== null && goods.goods_state !== undefined) {
					findResult.goods_state = goods.goods_state
				}
				if (goods.goods_count !== null && goods.goods_count !== undefined) {
					findResult.goods_count = goods.goods_count
				}
				//持久化存储到本地
				this.commit('m_cart/saveToStorage')
			}
		},
		removeGoodsById(state, goods_id) {
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)
			this.commit('m_cart/saveToStorage')
		},
		updateAllGoodsState(state, newState) {
			state.cart.forEach(x => x.goods_state = newState)
			this.commit('m_cart/saveToStorage')
		}
	},
	getters: {
		//统计购物车商品的总数量
		total(state) {
			return state.cart.reduce((acc, cur) => {
				if (cur.goods_count !== null && cur.goods_count != undefined) {
					acc += cur.goods_count
				}
				return acc
			}, 0)
		},
		checkedCount(state) {
			return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
		},
		checkedGoodsAmount(state) {
			return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count * item.goods_price,
				0).toFixed(2)
		}
	}
}